When you are looking to purchase an air compressor, it is important to already know what your compressed air requirements are. This will end up saving you a lot of time and money. The air tools that you will be using will display information on them or in their documentation, stating what power requirements they need to work efficiently. There are two power requirements that you will need to know; these are pressure and air flow ratings.
Air tools from different countries will present pressure ratings in different measurements. These will be either PSI (pounds per square inch) or BAR (meaning number of atmospheres). Whatever number is shown on the air tool is the recommended pressure that should be supplied by the air compressor to the air tool. Air flow rating is measured in either CFM (cubic feet) or LPM (litres per minute). This represents the required speed of compressed air to keep the air tool running continuously.
Calculate the LPM ratings of all the air tools that you intend to use. This will tell give you the minimum airflow capacity that will be needed from your air compressor in order to run those air tools at the same time. Make sure that you determine what the highest operational pressure is as your air compressor will need to be able to meet this pressure in order to allow that particular air tool to run to its optimum level of efficiency.